1289738640 has 80 divisors (see below), whose sum is σ = 4095737856. Its totient is φ = 335539200.

The previous prime is 1289738627. The next prime is 1289738657. The reversal of 1289738640 is 468379821.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1289738640.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55696 + ... + 75375.

Almost surely, 2^1289738640 is an apocalyptic number.

1289738640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1289738640 is an abundant number, since it is smaller than the sum of its proper divisors (2805999216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1289738640 is a wasteful number, since it uses less digits than its factorization.

1289738640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131128 (or 131122 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 48.

The square root of 1289738640 is about 35912.9313757593. The cubic root of 1289738640 is about 1088.5137108751.

The spelling of 1289738640 in words is "one billion, two hundred eighty-nine million, seven hundred thirty-eight thousand, six hundred forty".